Coated metal article and manufacture thereof



D. R. WARD Oct. 31, 1933.

' COATED METAL ARTICLE AND MANUFACTURE THEREOF Filed Oct. 1, 1929Patented Oct. 31, 1933 1,933,401

UNITED STATES PATENT OFFICE COATED METAL ARTICLE AND MANU- FACTURETHEREOF David R. Ward, Struthers, Ohio, assignor to The Youngstown Sheetand Tube Company, Youngstown, Ohio, a corporation of Ohio ApplicationOctober 1, 1929. Serial No. 396,444 16 Claims. (Cl. Ell-70.2)

This invention relates to a coated metallic arand surrounded by anon-oxidizing or reducing ticle and a method and apparatus for makingthe atmosphere. This prevents oxidation of the coatsame, and is hereinparticularly described as aping material and removes the necessity ofhaving plied to the lead coating of steel strips. a fluxing agentpresent to dissolve the oxides Any attempts to apply a lead coatingdirect to which would form in the presence of air.

steel by processes heretofore known have resulted If desired, thefixation rolls may be preceded by in coatings having pin holes thereinand some of sizing rolls which determine the amount of coatthe fluxingagents have been retained on the ing material which is applied per unitof area metal. The pin holes and retained flux both inof the base.

duce corrosion efiects. These pin holes are at- The use of my processand apparatus results 65 tributed to the combined action of escapinghyin a new product substantially free from pin holes drogen absorbed bythe base metal in the pickand having improved corrosion-resistantpropling operation, and to the surface tension of the erties. lead. Thesurface tension of the lead is suf- The accompanying figure of drawingillustrates ficiently high that it tends to produce globules on inlongitudinal vertical section a present pre- 70 the surface of the basematerial during the procferred embodiment of the invention as applied toess of solidification, because lead does not wet the lead coating of acontinuous strip. steel. In the apparatus shown in the drawing, strip Iprovide for applying the metallic coating and material S is fedcontinuously through a pickling substantially simultaneously cooling thesame and tank 2 under a guide roll 3, and upwardly through 75 acting onthe surface, as by compression rollers, a dry flux box 4. The flux box 4is filled with t pr v nt f rmat f pin holes or to se any a suitable fluxsuch as zinc chloride, ammonium pin holes which may be formed andproduce subchloride, or both. The material is still wet from stantialcontinuity of the coating material. Prefthe pickling tank when it passesthrough the a y t e base iS fed through a bath of the flux box 4.Hydrochloric acid is preferably em- 80 coating metal and is engagedalmost immediately ployed for pickling. The flux box is closed off atafter'it leaves the bath, a by a P of rolls, Which the bottom by rolls 5between which the wet strip are maintained at such temperature as tofreeze i mi The use of rolls 5 prevents choking of the adherent atin maia While at the same the box at the bottom and at the same time closestime, by compression, overcoming the surface tenit ofi against leakageof th dry flux, 85 SiOn fi ll, and tendency to fl P 110165, The materialpasses upwardly from the flux box Closing y p 110165 which y be formed-4 over a guide roll 6 and then downwardly through The material ispreferably fluxed before enterflux b '7 containing a it bl lt flux ingthe bath and is wiped scrubbed 80 as 170 such as those now in use. Thematerial passes g remove any es api s s or flux adhering to t e throughthe flux box 7 directly into a bath 8 of 90 u a ra ly th wip s effectedwhile molten lead contained in a lead pot 9, which is the material ismoving in a substantially vertical maintained at proper temperature byany suitdirection, whereby neither surface of the material m means (notshown) The material travels lies above the gas bubbles which are wipedoff. downwardly and passes around a guide r011 10 If the wiped offbubbles in their natural upward submerged in the lead. 95 travel throughthe bath were to be stopped in A wiper 11 is placed above the guide r01110 such travel by a surface of the base material, they so as to engageboth surfaces of the Strip in would tertd to adhere to the its verticaltravel from the guide roll 6 to the 53:22:33; figzgg alloymg o 8 baseguide roll 10. The rate of travel of the strip The base preferablypasses through a dry flux material is g g absorbed on its way to thecoating bath, and then through hydrogen produce tiring e pic ng operaaflux box adjacent the u f of the coating tlon escapes before the wlperll is reached. The

material. This insures adequate fluxing of the Wlper may be made I anysulteble mammal, such t i and d in t production of a as woven asbestosreinforced with wlre and car- 105 tinuous uninterrupted coating. ried insuitable rigid frame members, as shown. The rolls employed for thefixation of the coat- The w p is effective for mechanically mo ingmaterial on the base, that is to say, the rolls ing gas bubbles adheringto the surface of the which compress and cool the coating, are prefbasematerial, and since the strip extends ver- 55 erably arranged in achamber lying over the bath tically upwardly fr m th w p the gases ar110 free to travel to the top of the lead bath and pass off to theatmosphere.

By the time the base reaches the guide roll 10 it is highly heated, andthe lead in the bath becomes alloyed therewith as the strip travels fromthe guide roll 10 to a pair of rolls 12, similar to the so-called wipingrolls used in galvanizing practice. These rolls run partly in and partlyout of the lead bath so that when the material leaves the same, it isabove the bath. The spacing of the rolls is adjusted in any desiredmanner so as to determine the amount of lead which passes upwardly withthe base.

The rolls 12 are enclosed in a chamber 13 in which a neutral or reducingatmosphere is maintained. This prevents oxidation of the hot lead afterit leaves the bath. v

As the coated material travels upwardly from the rolls 12, the surfacetension of the lead tends to collect the coating into globules, thuscausing a discontinuous coating. This condition, if not corrected,results in pin holes in the final product.

A pair of fixation rolls 14 is arranged in the chamber 13 a shortdistance above the sizing rolls 12. These rolls are hollow and arewatercooled. They are efiective for mechanically acting on the stillmolten coating so as to squeeze down any globules, thus rendering thecoating again continuous, and for freezing or setting the lead so thatany tendency of the same to again collect into globules and produce adiscontinuous coating is immediately eliminated. The material,therefore, when it leaves the fixation rolls 14, is a ferrous basehaving a coating of lead applied directly thereto, the coating beingsubstantially free from pin holes; This material travels upwardly over aguide roll 15 and thence out of the apparatus. The force necessary topull the strip through the apparatus may be supplied by a coiler or bypinch rolls 16, as desired. All rolls may or may not be driven asdesired.

While the rolls 14 serve to chill the fiuid lead under pressure, thesolidified lead still has a high degree of plasticity and because thereare no oxides present, it will be rolled into a uniform and continuoussurface. As a matter of fact, the operations of rolling and chillingoccur simultaneously and by proper regulation of the amount of coolingfluid supplied, the continuity of surface is probably obtainedapproximately when the solidification point of the lead is reached.

My process is of value not only in the coating of lead on steel, butalso for the coating of other materials such as lead on brass or copper,or aluminum on iron, which do not readily alloy with the base. In thisconnection see Protective Metallic Coatings by Henry S. Rawdon of the U.S. Bureau of Standards, page 136, where pin holes intin coatings arediscussed.

It will be noted from the drawing that a coating 17 is provided over thebath to prevent oxidation of lead. This coating may be the fluxmaterial, powdered charcoal, or other suitable substance. It will befurther noted that this protective coating is not applied to thatportion of the bath lying within the chamber 13, and that the walls ofthe chamber are extended below the lead line so as to prevent any of thecoating material from entering. There is no need to protect the surfaceof the lead from oxidation by a coating such as 17 in the chamber 13because of the reducing or non-oxidizing atmosphere therein. Because ofthis provision the rolls 12 do not pick up dross, but maintain theirshape and cleanness of surface indefinitelyl While the invention hasbeen described as particularly applied to the coating of strips, it willbe understood that it is not to be limited but may be also used for thecoating of other articles such as wire, rods, sheets, or pipes. It willbe understood, therefore, that while I have illustrated and describedthe preferred form of the invention as applied to the lead coating ofstrips, it is not to be limited to the form shown but may be otherwiseembodied or practiced within the scope of the following claims.

I claim:-

1. In the method of applying a metallic coating to a metallic base, thesteps consisting in feeding the base through a molten bath of thecoating metal, engaging the issuing material while the coating is stillat a high temperature, and substantially simultaneously mechanicallyconfining, compressing and cooling the same in a non-oxidizingatmosphere.

2. In the method of applying a metallic coating to a metallic base, thesteps consisting in feeding the base through a molten bath of thecoating metal, engaging the issuing material while the coating is stillat a high temperature, and substantially simultaneously mechanicallyconfining, compressing and cooling the same in a reducing atmosphere.

3. In the method of applying a metallic coating to a metallic base, thesteps consisting in feeding the base through a molten bath of thecoating metal, passing the material direct from the bath into anon-oxidizing atmosphere, and before the coating has set theresubstantially simultaneously mechanically confining, compressing andcooling the same.

4. In the method of applying a metallic coating to a metallic base, thesteps consisting in passing a base through a molten bath, wiping thesurface of the base while the same is submerged and is in such positionas to insure uniform release of gases from both sides thereof, andcontinuously moving the base away from the wiping point while it ismaintained in the same'relative position to permit uniform release ofgases from both sides thereof.

5. In the method of applying a metallic coating to a metallic base, thesteps consisting in supplying a wet pickled base, applying a fluxthereto while still wet, heating the fiuxed base, wiping the same whilethe portion being wiped is vertically disposed within a coating bath,and applying a coating.

6. In the method of applying a metallic coating to a metallic base, thesteps consisting in heating a base, wiping the same and. applying acoating, and thereafter compacting the coating before it has set so asto close pin holes and simultaneously solidify the coating.

7. In the method of applying a metallic coating to a metallic base, thesteps consisting in heating a base, wiping the same and applying 140 acoating, and thereafter compacting the coating material in anon-oxidizing atmosphere and before it has set so as to close pin holesand simultaneously solidify the coating.

8. In the method of applying a metallic coating to a metallic base, thesteps consisting in fluxing a base and heating the same, wiping theheated base, applying a coating material thereto, and thereaftercompacting the coating ma terial before it has set so as to close anypin 150 to a metallic base, comprising a holes therein andsimultaneously solidify the same.

9. Apparatus for applying a metallic coating to a metallic base,comprising means whereby a coating material is applied to the base, andmeans effective on the pressure in a non-oxidizing atmosphere.

10. Apparatus for applying a metallic coating to a metallic base,comprising a container for a bath of molten coating material, meanswhereby the base is guided through the container, means for engaging theissuing material before the coating has set and substantiallysimultaneously mechanically confining, compressing and cooling the same,and means for maintaining the issuing material in a non-oxidizingcondition until the last-mentioned means has acted thereon.

11. Apparatus for applying a metallic coating to a metallic base,comprising a container for a bath of coating material, achamberextending upwardly from the bath, means for guiding base materialthrough the bath and the chamber, the chamber being adapted formaintaining a nonoxidizing atmosphere around the base as it travelstherethrough, and means in the chamber for cooling the coated base underpressure. I

12. Apparatus for applying a metallic co ting containei' for a bath ofmolten coating material, means for guiding the base therethrough, meanswhereby the base is heated, means for wiping the base while at elevatedtemperature, sizing means for coating before it has set for chilling theapplied coating under rolling determining the amount of coating materialon the base as it leaves the bath, and means for setting and cooling thecoated base under pressure.

13. Apparatusfor applying a metallic coating to a metallic base,comprising a container for a bath of molten coating material, guidemeans whereby the base is directed upwardly and then downwardly into thebath, and means for applying a flux during its upward travel.

14. Apparatus for applying a metallic coating to a metallic base,comprising a pickler, means for applying a dry fluxing material to thewet base as it leaves the pickler, and a container for a bath of moltencoating material adapted to coat the fluxed base.

-15. In the method of applying a metallic coating to a metallic base,the steps consisting in feeding the base'through a molten bath of thecoating metal, withdrawing the coated base, applying pressure to thecoated base before the coating has set, and chilling the base andcoating I coating metal, withdrawing the coated base, ap-

plying pressure to the coated base before l5h coating has set, andchilling the base and coating at the point of pressure application whilemaintaining said point under a non-oxidizing atmosphere.

DAVID R. WARD.

